Among the countries all over the world, the hemodialysis therapy is most widely practiced in Japan. This therapy over an extended time, however, induces various serious problems. The hemodialysis therapy for a long time, for example, causes the onset of complications such as cardiovascular disorder, anemia, abnormal bone metabolism, dysbolism, and/or immunodeficiency. In addition, it is said that 60-80% of the hemodialysis patients suffer from pruritus cutaneus. Although pruritus cutaneus itself does not impose direct threatening on the life of the patients, its persistent and chronic torment, night and day, is unbearable to the patients, both physically and mentally. From the view point of the maintenance and improvement in the quality of life, pruritus cutaneus is now a big problem in the treatment of the patients.
As a possible cause of pruritus cutaneus, 1. stimulation of the nerve ending by a certain substance accumulated in the blood by renal failure, 2. a decline in the pruritus threshold value due to change in the pH value, etc., or 3. abnormal secretion by the skin glands such as sebaceous glands and sweat glands, is suspected but it Is not yet clear what is responsible for it. For its treatment, antihistaminic agent is generally administered but it has limitation in its efficacy. Besides, due to its side effects like drowsiness, vertigo or generalized malaise, its administration must be discontinued in many cases. In addition, anti-allergic agent, adrenocortical agent or tranquilizer is administered but no agent alone can relieve the patients from the torment and establishment of an effective therapy has been expected.